Self-pressurization vehicle-mounted liquid hydrogen storage and supply system and heat management method

Abstract

The invention provides a self-pressurization vehicle-mounted liquid hydrogen storage and supply system and a heat management method. The self-pressurization vehicle-mounted liquid hydrogen storage and supply system comprises a liquid hydrogen storage unit, a filling system, a liquid hydrogen supply system, a liquid hydrogen self-pressurization system and a cooling system. The filling system is used for supplementing liquid hydrogen to the liquid hydrogen storage unit; the liquid hydrogen storage unit is communicated with the fuel cell stack through the liquid hydrogen supply system and is used for supplying hydrogen to the fuel cell stack; the liquid hydrogen storage unit and the liquid hydrogen self-pressurization system form a closed loop, and vaporized liquid hydrogen is used for increasing the pressure in the liquid hydrogen storage unit; the cooling system is used for heat exchange of the fuel cell stack, the vaporizer in the liquid hydrogen supply system and the vaporizer in the liquid hydrogen self-pressurization system. By means of the liquid hydrogen self-pressurization system, stable-pressure supply of liquid hydrogen can be guaranteed, and the overall heat efficiency of the vehicle-mounted liquid hydrogen storage and supply system is improved.

Description

Technical Field

[0001] The present invention relates to the field of on-board liquid hydrogen storage and supply systems and thermal management of hydrogen fuel cell vehicles, and in particular to a self-pressurizing on-board liquid hydrogen storage and supply system and a thermal management method. Background Art

[0002] Hydrogen energy is widely used in the fields of aerospace and transportation due to its advantages such as wide raw material sources, high energy density, and zero emissions during the use phase. Low-temperature liquid hydrogen storage is the most ideal form of hydrogen storage and transportation, with the largest mass hydrogen storage density and volume hydrogen storage density second only to solid hydrogen storage. Therefore, about 1 / 3 of hydrogen refueling stations abroad are liquid hydrogen refueling stations.

[0003] The refueling process of directly refueling liquid hydrogen into liquid hydrogen fuel cell vehicles will greatly simplify the refueling process based on liquid hydrogen refueling stations and improve energy efficiency. The on-board liquid hydrogen storage and supply system is an important part of liquid hydrogen fuel cell vehicles. In order to avoid the gradual decrease in tank pressure with the supply of liquid hydrogen, resulting in a large amount of liquid hydrogen remaining in the tank and causing supply difficulties, the tank self-pressurization method is required to ensure the stable supply of liquid hydrogen under on-board conditions.

[0004] The existing vehicle-mounted LNG storage tank self-pressurization method uses electric heating pressurization. However, due to the higher requirements for liquid hydrogen storage, the electric heating pressurization method cannot guarantee good safety. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a self-pressurizing vehicle-mounted liquid hydrogen storage and supply system and a thermal management method. Through the liquid hydrogen self-pressurizing system, the stable pressure supply of liquid hydrogen can be ensured, thereby improving the overall thermal efficiency of the vehicle-mounted liquid hydrogen storage and supply system.

[0006] The present invention achieves the above technical objectives through the following technical means.

[0007] A self-pressurizing on-board liquid hydrogen storage and supply system comprises a liquid hydrogen storage unit, a filling system, a liquid hydrogen supply system, a liquid hydrogen self-pressurizing system and a cooling system; the filling system is used to replenish liquid hydrogen in the liquid hydrogen storage unit; the liquid hydrogen storage unit is connected to a fuel cell stack through the liquid hydrogen supply system, and is used to supply hydrogen to the fuel cell stack; the liquid hydrogen storage unit and the liquid hydrogen self-pressurizing system form a closed loop, and the pressure in the liquid hydrogen storage unit is increased by using vaporized liquid hydrogen; the cooling system is used for heat exchange between the fuel cell stack, a vaporizer in the liquid hydrogen supply system and a vaporizer in the liquid hydrogen self-pressurizing system.

[0008] Furthermore, the liquid hydrogen self-pressurization system includes a third cryogenic fluid one-way valve, a third flow control valve, a second water bath vaporizer and a second safety valve. A branch of the outlet of the liquid hydrogen storage unit sequentially passes through the third cryogenic fluid one-way valve, the third flow control valve, the second water bath vaporizer and the gas inlet at the top of the liquid hydrogen storage unit to form a closed loop. The second water bath vaporizer is used to vaporize liquid hydrogen and input it into the liquid hydrogen storage unit for internal pressurization through heat exchange with the coolant of the cooling system; a second safety valve is provided at the gas inlet at the top of the liquid hydrogen storage unit.

[0009] Furthermore, the liquid hydrogen storage unit is provided with a pressure sensor for detecting the internal pressure of the liquid hydrogen storage unit; when the pressure inside the liquid hydrogen storage unit is greater than or equal to a set value, the liquid hydrogen self-pressurization system does not work; when the pressure inside the liquid hydrogen storage unit is less than the set value, the third flow control valve is controlled to open so that the pressure inside the liquid hydrogen storage unit is greater than the set value.

[0010] Further, the liquid hydrogen supply system includes a second cryogenic fluid one-way valve, a first flow control valve, an air-temperature vaporizer, a first water-bath vaporizer, a buffer tank, a second flow control valve and a first safety valve;

[0011] The liquid outlet of the liquid hydrogen storage unit is connected to the air-temperature vaporizer through the second cryogenic fluid one-way valve and the first flow control valve. The air-temperature vaporizer is used to preliminarily heat and vaporize the liquid hydrogen. The mixed medium of liquid hydrogen and hydrogen is input into the first water bath vaporizer, and the mixed medium is completely converted into hydrogen through heat exchange with the coolant of the cooling system; the outlet of the first water bath vaporizer is connected to the fuel cell stack through the buffer tank, the second flow control valve and the first safety valve; the outlet of the first water bath vaporizer is provided with a first temperature sensor for monitoring the hydrogen temperature.

[0012] Furthermore, the heat exchange area of ​​the vaporizer in the liquid hydrogen supply system is greater than twice the heat exchange area of ​​the vaporizer in the liquid hydrogen self-pressurization system, and the nominal diameter of the pipeline of the liquid hydrogen self-pressurization system does not exceed 1 / 3 of the nominal diameter of the pipeline of the liquid hydrogen self-pressurization system.

[0013] Further, the cooling system includes a fuel cell stack cooling system and a vaporizer cooling system;

[0014] The fuel cell stack cooling system comprises a deionized water tank, a fourth flow control valve, a heat exchanger and a deionized water pump; the fuel cell stack, the deionized water pump, the fourth flow control valve and the heat exchanger form a circulation pipeline;

[0015] The vaporizer cooling system includes a coolant tank, a cooling water pump and a heater; the coolant tank outlet is connected to the cooling water pump inlet, the coolant tank inlet is connected to the heater, the vaporizer cooling pipeline in the liquid hydrogen self-pressurizing system is connected in series with the heat exchanger cooling pipeline, and then connected in parallel with the vaporizer cooling pipeline in the liquid hydrogen supply system between the cooling water pump outlet and the heater inlet.

[0016] Furthermore, a second temperature sensor is installed in the pipeline of the fuel cell stack cooling system to monitor the temperature of deionized water flowing out of the fuel cell; a third temperature sensor is provided at the outlet of the vaporizer cooling pipeline in the liquid hydrogen self-pressurization system to monitor the temperature of the coolant flowing out of the vaporizer in the liquid hydrogen self-pressurization system; the cooling water pump is connected to the inlet of the vaporizer cooling pipeline in the liquid hydrogen self-pressurization system through a first three-way valve, and the other outlet of the first three-way valve is connected to the inlet of the vaporizer cooling pipeline in the liquid hydrogen supply system; the heater inlet is connected to the outlet of the heat exchanger cooling pipeline through a second three-way valve, and the other inlet of the second three-way valve is connected to the outlet of the vaporizer cooling pipeline in the liquid hydrogen supply system.

[0017] Furthermore, it also includes a control system, which controls the first three-way valve and the second three-way valve according to the internal pressure of the liquid hydrogen storage unit measured by the pressure sensor, so that the coolant tank, the cooling water pump, the vaporizer cooling pipeline in the liquid hydrogen self-pressurization system, the heat exchanger cooling pipeline and the heater form a circulation pipeline, or the coolant tank, the cooling water pump, the vaporizer cooling pipeline and the heater in the liquid hydrogen supply system form a circulation pipeline.

[0018] A thermal management method for a self-pressurizing on-board liquid hydrogen storage and supply system comprises the following steps:

[0019] The pressure sensor obtains the internal pressure of the liquid hydrogen storage unit;

[0020] When the pressure in the liquid hydrogen storage unit is greater than or equal to a set value, the control system controls the first three-way valve to connect the cooling water pump with the vaporizer cooling pipeline in the liquid hydrogen supply system, and the control system controls the second three-way valve to connect the vaporizer cooling pipeline in the liquid hydrogen supply system with the heater;

[0021] When the pressure in the liquid hydrogen storage unit is less than a set value, the control system controls the third flow control valve to open, so that the liquid hydrogen storage unit and the liquid hydrogen self-pressurization system form a closed loop; the control system controls the first three-way valve to connect the cooling water pump with the vaporizer cooling pipeline in the liquid hydrogen self-pressurization system, and the control system controls the second three-way valve to connect the vaporizer cooling pipeline in the liquid hydrogen self-pressurization system with the heater.

[0022] Furthermore, when the pressure in the liquid hydrogen storage unit is less than a set value, the control system measures the temperature of the coolant flowing out of the vaporizer in the liquid hydrogen self-pressurizing system according to the third temperature sensor, controls the flow of the cooling water pump and the opening of the three flow control valves, so that the pressure in the liquid hydrogen storage unit is maintained at 1 to 1.2 times the set value, and the temperature of the coolant flowing out of the vaporizer in the liquid hydrogen self-pressurizing system is controlled at -35°C to -25°C; the coolant flowing out of the vaporizer in the liquid hydrogen self-pressurizing system enters the heat exchanger of the fuel cell stack cooling system, so that the temperature of the deionized water in the fuel cell stack cooling system is reduced to 10 to 20°C.

[0023] The beneficial effects of the present invention are:

[0024] 1. The self-pressurizing vehicle-mounted liquid hydrogen storage and supply system and thermal management method described in the present invention, liquid hydrogen is filled through the filling port, flows through the first cryogenic fluid one-way valve, and finally is filled into the vehicle-mounted liquid hydrogen bottle from the bottom. Liquid hydrogen is discharged from the liquid outlet at the bottom of the liquid hydrogen bottle, flows through the second cryogenic fluid one-way valve and the first flow control valve, flows into the air-temperature vaporizer for preliminary heating and vaporization into hydrogen, and flows into the first water bath vaporizer, exchanges heat with the coolant of the fuel cell external cooling system, and further heats and heats up. The first water bath vaporizer is provided with a first temperature sensor at the hydrogen outlet to monitor the hydrogen temperature. The heated hydrogen flows into the buffer tank to stabilize the pressure, and is supplied into the fuel cell stack through the second flow control valve and the safety valve. Liquid hydrogen flows into the second water bath vaporizer through the cryogenic fluid one-way valve and the third flow control valve, exchanges heat with the coolant of the fuel cell external cooling system and vaporizes, and reaches the gas phase space at the top of the liquid hydrogen bottle to achieve self-pressurization. A pressure sensor and a safety valve are provided at the top of the liquid hydrogen bottle.

[0025] 2. The self-pressurized on-board liquid hydrogen storage and supply system and thermal management method described in the present invention can effectively prevent the pressure in the tank from gradually decreasing with the supply of liquid hydrogen, resulting in a large amount of liquid hydrogen remaining in the storage tank, thereby achieving a stable pressure supply of liquid hydrogen under vehicle-mounted conditions. The coolant after heat exchange and cooling of the self-pressurized liquid hydrogen inside the second water bath vaporizer flows into the heat exchanger to exchange heat with the deionized water in the cooling system of the fuel cell, and returns to the deionized water tank to achieve circulating cooling, ensuring that the fuel cell operates in the optimal temperature range. Through precise control of the coolant flow and temperature inside and outside the fuel cell stack, the cooling effect and waste heat utilization of the fuel cell stack are greatly improved, the liquid hydrogen cooling energy is fully utilized, the overall energy utilization rate is improved, and the development of on-board liquid hydrogen technology is promoted. Therefore, the present invention provides a self-pressurized on-board liquid hydrogen storage and supply system and a thermal management method. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. The drawings described below are some embodiments of the present invention. For ordinary technicians in this field, it is obvious that other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 This is a schematic diagram of the self-pressurizing on-board liquid hydrogen storage and supply system described in the present invention.

[0028] In the figure:

[0029] 1-on-board liquid hydrogen bottle; 2-first low-temperature fluid one-way valve; 3-filling port; 4-second low-temperature fluid one-way valve; 5-first flow control valve; 6-air-temperature vaporizer; 7-first water-bath vaporizer; 8-first temperature sensor; 9-buffer tank; 10-second flow control valve; 11-safety valve; 12-fuel cell stack; 13-deionized water tank; 14-second temperature sensor; 15-deionized water pump; 16-fourth flow control valve; 17-heat exchanger; 18-third low-temperature fluid one-way valve; 19-third flow control valve; 20-second water-bath vaporizer; 21-pressure sensor; 22-second safety valve; 23-coolant tank; 24-cooling water pump; 25-first three-way valve; 26-third temperature sensor; 27-second three-way valve; 28-heater. DETAILED DESCRIPTION

[0030] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0031] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "axial", "radial", "vertical", "horizontal", "inner", "outer" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0032] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] like Figure 1 As shown, the solid lines in the figure represent the flow paths of liquid hydrogen and hydrogen gas, the dashed lines represent the flow path of the coolant (50% ethylene glycol aqueous solution) outside the fuel cell, and the center line represents the flow path of the coolant (deionized water) inside the fuel cell. The self-pressurizing on-board liquid hydrogen storage and supply system of the present invention comprises an on-board liquid hydrogen bottle 1, a filling system, a liquid hydrogen supply system, a liquid hydrogen self-pressurizing system and a cooling system; a filling port 3 is provided on the upper portion of the on-board liquid hydrogen bottle 1, a first cryogenic fluid one-way valve 2 is installed on the filling port 3, and the filling system is connected to the filling port 3 for replenishing liquid hydrogen in the on-board liquid hydrogen bottle 1;

[0034] The on-board liquid hydrogen bottle 1 is connected to the fuel cell stack 12 through a liquid hydrogen supply system, and is used to supply gaseous hydrogen to the fuel cell stack 12; the on-board liquid hydrogen bottle 1 and the liquid hydrogen self-pressurization system form a closed loop, and the vaporized liquid hydrogen is used to increase the pressure in the on-board liquid hydrogen bottle 1; the cooling system is used for heat exchange between the fuel cell stack 12, the vaporizer in the liquid hydrogen supply system, and the vaporizer in the liquid hydrogen self-pressurization system.

[0035] like Figure 1 As shown, the liquid hydrogen self-pressurization system includes a third cryogenic fluid one-way valve 18, a third flow control valve 19, a second water bath vaporizer 20 and a second safety valve 22. A branch of the outlet of the on-board liquid hydrogen bottle 1 passes through the third cryogenic fluid one-way valve 18, the third flow control valve 19, the second water bath vaporizer 20 and the gas inlet at the top of the on-board liquid hydrogen bottle 1 to form a closed loop. The second water bath vaporizer 20 is used to vaporize liquid hydrogen and input it into the on-board liquid hydrogen bottle 1 for internal pressurization by exchanging heat with the coolant of the cooling system; a second safety valve 22 is provided at the gas inlet at the top of the on-board liquid hydrogen bottle 1. Liquid hydrogen flows into the second water bath vaporizer 20 through the third cryogenic fluid one-way valve 18 and the third flow control valve 19, exchanges heat with the coolant of the fuel cell external cooling system and vaporizes, and reaches the gas phase space at the top of the liquid hydrogen bottle to achieve self-pressurization.

[0036] The liquid hydrogen storage unit is provided with a pressure sensor 21 for detecting the internal pressure of the onboard liquid hydrogen bottle 1; when the pressure in the onboard liquid hydrogen bottle 1 is greater than or equal to the set value, the liquid hydrogen self-pressurization system does not work; when the pressure in the onboard liquid hydrogen bottle 1 is less than the set value, the third flow control valve 19 is controlled to open so that the pressure in the liquid hydrogen storage unit is greater than the set value. The set value is generally 1MPa.

[0037] like Figure 1 As shown, the liquid hydrogen supply system includes a second cryogenic fluid one-way valve 4, a first flow control valve 5, an air-temperature vaporizer 6, a first water-bath vaporizer 7, a buffer tank 9, a second flow control valve 10 and a first safety valve 11;

[0038] Another branch of the outlet of the on-board liquid hydrogen bottle 1 is connected to the air-temperature vaporizer 6 through the second cryogenic fluid one-way valve 4 and the first flow control valve 5. The air-temperature vaporizer 6 is used to preliminarily heat and vaporize the liquid hydrogen. The mixed medium of liquid hydrogen and hydrogen is input into the first water bath vaporizer 7, and the mixed medium is completely converted into hydrogen through heat exchange with the coolant of the cooling system; the outlet of the first water bath vaporizer 7 is connected to the fuel cell stack 12 through the buffer tank 9, the second flow control valve 10 and the first safety valve 11; the outlet of the first water bath vaporizer 7 is provided with a first temperature sensor 8 for monitoring the hydrogen temperature. Liquid hydrogen is discharged from the liquid outlet at the bottom of the liquid hydrogen bottle, flows through the second cryogenic fluid one-way valve 4 and the first flow control valve 5, flows into the air-temperature vaporizer 6 for preliminary heating and vaporization into hydrogen, and flows into the first water bath vaporizer 7 to exchange heat with the coolant of the fuel cell external cooling system for further heating. A first temperature sensor 8 is provided at the hydrogen outlet of the first water bath vaporizer 7 to monitor the hydrogen temperature. The heated hydrogen flows into the buffer tank 9 to stabilize the pressure, and is supplied into the fuel cell stack 12 through the second flow control valve 10 and the first safety valve 11.

[0039] The heat exchange area of ​​the first water bath vaporizer 7 in the liquid hydrogen supply system is twice greater than the heat exchange area of ​​the second water bath vaporizer 20, and the nominal diameter of the liquid hydrogen self-pressurizing system pipeline does not exceed 1 / 3 of the nominal diameter of the liquid hydrogen self-pressurizing system pipeline. Because the liquid hydrogen self-pressurizing system pipeline only needs a small flow of liquid hydrogen, the pressure generated by it can meet the purpose of self-pressurization of the on-board liquid hydrogen bottle 1.

[0040] like Figure 1As shown, the cooling system includes a fuel cell stack cooling system and a vaporizer cooling system; the fuel cell stack cooling system includes a deionized water tank 13, a fourth flow control valve 16, a heat exchanger 17 and a deionized water pump 15; the fuel cell stack 15 and the deionized water pump 15, the fourth flow control valve 16 and the heat exchanger 17 form a circulation pipeline; the vaporizer cooling system includes a coolant tank 23, a cooling water pump 24 and a heater 28; the coolant tank 23 outlet is connected to the cooling water pump 24 inlet, the coolant tank 23 inlet is connected to the heater 28, the cooling pipeline of the second water bath vaporizer 20 is connected in series with the cooling pipeline of the heat exchanger 17, and then connected in parallel with the cooling pipeline of the first water bath vaporizer 7 between the cooling water pump 24 outlet and the heater 28 inlet.

[0041] A second temperature sensor 14 is installed in the pipeline of the fuel cell stack cooling system for monitoring the temperature of deionized water flowing out of the fuel cell; a third temperature sensor 26 is provided at the outlet of the cooling pipeline of the second water bath vaporizer 20 for monitoring the temperature of the coolant flowing out of the second water bath vaporizer 20; the cooling water pump 24 is connected to the cooling pipeline inlet of the second water bath vaporizer 20 through a first three-way valve 25, and the other outlet of the first three-way valve 25 is connected to the cooling pipeline inlet of the first water bath vaporizer 7; the inlet of the heater 28 is connected to the cooling pipeline outlet of the heat exchanger 17 through a second three-way valve 27, and the other inlet of the second three-way valve 27 is connected to the cooling pipeline outlet of the first water bath vaporizer 7.

[0042] It also includes a control system, which controls the first three-way valve 25 and the second three-way valve 27 according to the internal pressure of the liquid hydrogen storage unit measured by the pressure sensor 21, so that the coolant tank 23, the cooling water pump 24, the cooling pipeline of the second water bath vaporizer 20, the cooling pipeline of the heat exchanger 17 and the heater form a circulation pipeline, or the coolant tank 23, the cooling water pump 24, the cooling pipeline of the first water bath vaporizer 7 and the heater form a circulation pipeline.

[0043] The thermal management method of the self-pressurizing vehicle-mounted liquid hydrogen storage and supply system of the present invention comprises the following steps:

[0044] The pressure sensor 21 obtains the internal pressure of the liquid hydrogen storage unit;

[0045] When the pressure in the on-board liquid hydrogen bottle 1 is greater than or equal to 1 MPa, the control system controls the first three-way valve 25 to connect the cooling water pump 24 with the cooling pipeline of the first water bath vaporizer 7, and the control system controls the second three-way valve 27 to connect the cooling pipeline of the first water bath vaporizer 7 with the heater;

[0046] When the pressure in the on-board liquid hydrogen bottle 1 is less than 1 MPa, the control system controls the third flow control valve 19 to open, so that the on-board liquid hydrogen bottle 1 and the liquid hydrogen self-pressurization system form a closed loop; the control system controls the first three-way valve 25 to connect the cooling water pump 24 with the cooling pipeline of the second water bath vaporizer 20, and the control system controls the second three-way valve 27 to connect the cooling pipeline of the second water bath vaporizer 20 with the heater 28.

[0047] In order to better realize the present invention, the on-board liquid hydrogen storage and supply system is associated with the fuel cell cooling system. The liquid hydrogen and coolant demand flow rates in the second water bath vaporizer for self-pressurization of the liquid hydrogen bottle are relatively small. When the pressure in the liquid hydrogen storage unit is less than the set value, the control system measures the coolant temperature flowing out of the second water bath vaporizer 20 according to the third temperature sensor 26, controls the flow rate of the cooling water pump 24 and the opening of the three flow control valves 19, so that the pressure in the on-board liquid hydrogen bottle 1 is maintained at 1-1.2MPa, and the coolant temperature flowing out of the second water bath vaporizer 20 is controlled at -35°C to -25°C; the coolant flowing out of the second water bath vaporizer 20 enters the heat exchanger 17 of the fuel cell stack cooling system, so that the temperature of the deionized water of the fuel cell stack cooling system is reduced to 10-20°C, which greatly improves the cooling effect and waste heat utilization of the fuel cell stack, thereby improving the thermal efficiency of the self-pressurized on-board liquid hydrogen storage and supply system.

[0048] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0049] The series of detailed descriptions listed above are only specific descriptions of feasible embodiments of the present invention. They are not intended to limit the scope of protection of the present invention. All equivalent embodiments or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A self-pressurizing vehicle-mounted liquid hydrogen storage and supply system, characterized in that: The invention comprises a liquid hydrogen storage unit, a filling system, a liquid hydrogen supply system, a liquid hydrogen self-pressurizing system and a cooling system; the filling system is used to replenish liquid hydrogen in the liquid hydrogen storage unit; the liquid hydrogen storage unit is connected to a fuel cell stack (12) through the liquid hydrogen supply system and is used to supply hydrogen to the fuel cell stack (12); the liquid hydrogen storage unit and the liquid hydrogen self-pressurizing system form a closed loop, and the pressure in the liquid hydrogen storage unit is increased by using vaporized liquid hydrogen; the cooling system is used for heat exchange between the fuel cell stack (12), a vaporizer in the liquid hydrogen supply system and a vaporizer in the liquid hydrogen self-pressurizing system.

2. The self-pressurizing vehicle-mounted liquid hydrogen storage and supply system according to claim 1 is characterized in that: The liquid hydrogen self-pressurization system comprises a third cryogenic fluid one-way valve (18), a third flow control valve (19), a second water bath vaporizer (20) and a second safety valve (22); a branch of the outlet of the liquid hydrogen storage unit passes through the third cryogenic fluid one-way valve (18), the third flow control valve (19), the second water bath vaporizer (20) and the gas inlet at the top of the liquid hydrogen storage unit in sequence to form a closed loop; the second water bath vaporizer (20) is used to vaporize the liquid hydrogen and input it into the liquid hydrogen storage unit for internal pressurization through heat exchange with the coolant of the cooling system; and a second safety valve (22) is provided at the gas inlet at the top of the liquid hydrogen storage unit.

3. The self-pressurizing vehicle-mounted liquid hydrogen storage and supply system according to claim 2 is characterized in that: The liquid hydrogen storage unit is provided with a pressure sensor (21) for detecting the internal pressure of the liquid hydrogen storage unit; when the pressure inside the liquid hydrogen storage unit is greater than or equal to a set value, the liquid hydrogen self-pressurization system does not work; when the pressure inside the liquid hydrogen storage unit is less than the set value, the third flow control valve (19) is controlled to open, so that the pressure inside the liquid hydrogen storage unit is greater than the set value.

4. The self-pressurizing vehicle-mounted liquid hydrogen storage and supply system according to claim 1, characterized in that: The liquid hydrogen supply system comprises a second cryogenic fluid one-way valve (4), a first flow control valve (5), an air-temperature vaporizer (6), a first water bath vaporizer (7), a buffer tank (9), a second flow control valve (10) and a first safety valve (11); The liquid outlet of the liquid hydrogen storage unit is connected to an air-temperature vaporizer (6) through a second cryogenic fluid one-way valve (4) and a first flow control valve (5); the air-temperature vaporizer (6) is used to initially heat and vaporize liquid hydrogen; a mixed medium of liquid hydrogen and hydrogen is input into a first water bath vaporizer (7); the mixed medium is completely converted into hydrogen through heat exchange with a coolant of a cooling system; the outlet of the first water bath vaporizer (7) is connected to a fuel cell stack (12) through a buffer tank (9), a second flow control valve (10) and a first safety valve (11); a first temperature sensor (8) is provided at the outlet of the first water bath vaporizer (7) for monitoring the temperature of hydrogen.

5. The self-pressurizing vehicle-mounted liquid hydrogen storage and supply system according to claim 1, characterized in that: The heat exchange area of ​​the vaporizer in the liquid hydrogen supply system is greater than twice the heat exchange area of ​​the vaporizer in the liquid hydrogen self-pressurization system, and the nominal diameter of the pipeline of the liquid hydrogen self-pressurization system does not exceed 1 / 3 of the nominal diameter of the pipeline of the liquid hydrogen self-pressurization system.

6. The self-pressurizing vehicle-mounted liquid hydrogen storage and supply system according to claim 1, characterized in that: The cooling system includes a fuel cell stack cooling system and a vaporizer cooling system; The fuel cell stack cooling system comprises a deionized water tank (13), a fourth flow control valve (16), a heat exchanger (17) and a deionized water pump (15); the fuel cell stack (15) and the deionized water pump (15), the fourth flow control valve (16) and the heat exchanger (17) form a circulation pipeline; The vaporizer cooling system comprises a coolant tank (23), a cooling water pump (24) and a heater (28); the coolant tank (23) outlet is connected to the cooling water pump (24) inlet, the coolant tank (23) inlet is connected to the heater (28), the vaporizer cooling pipeline in the liquid hydrogen self-pressurizing system is connected in series with the cooling pipeline of the heat exchanger (17), and then connected in parallel with the vaporizer cooling pipeline in the liquid hydrogen supply system between the cooling water pump (24) outlet and the heater (28) inlet.

7. The self-pressurizing vehicle-mounted liquid hydrogen storage and supply system according to claim 6, characterized in that: A second temperature sensor (14) is installed in the pipeline of the fuel cell stack cooling system for monitoring the temperature of deionized water flowing out of the fuel cell; a third temperature sensor (26) is provided at the outlet of the vaporizer cooling pipeline in the liquid hydrogen self-pressurizing system for monitoring the temperature of the coolant flowing out of the vaporizer in the liquid hydrogen self-pressurizing system; the cooling water pump (24) is connected to the inlet of the vaporizer cooling pipeline in the liquid hydrogen self-pressurizing system through a first three-way valve (25), and the other outlet of the first three-way valve (25) is connected to the inlet of the vaporizer cooling pipeline in the liquid hydrogen supply system; the inlet of the heater (28) is connected to the outlet of the cooling pipeline of the heat exchanger (17) through a second three-way valve (27), and the other inlet of the second three-way valve (27) is connected to the outlet of the vaporizer cooling pipeline in the liquid hydrogen supply system.

8. The self-pressurizing vehicle-mounted liquid hydrogen storage and supply system according to claim 6, characterized in that: The invention also includes a control system, which controls the first three-way valve (25) and the second three-way valve (27) according to the internal pressure of the liquid hydrogen storage unit measured by the pressure sensor (21), so that the coolant tank (23), the cooling water pump (24), the vaporizer cooling pipeline in the liquid hydrogen self-pressurization system, the heat exchanger (17) cooling pipeline and the heater form a circulation pipeline, or the coolant tank (23), the cooling water pump (24), the vaporizer cooling pipeline and the heater in the liquid hydrogen supply system form a circulation pipeline.

9. A thermal management method for a self-pressurizing on-board liquid hydrogen storage and supply system according to claim 8, characterized in that: The steps include: The pressure sensor (21) obtains the internal pressure of the liquid hydrogen storage unit; When the pressure in the liquid hydrogen storage unit is greater than or equal to a set value, the control system controls the first three-way valve (25) to connect the cooling water pump (24) with the vaporizer cooling pipeline in the liquid hydrogen supply system, and the control system controls the second three-way valve (27) to connect the vaporizer cooling pipeline in the liquid hydrogen supply system with the heater; When the pressure in the liquid hydrogen storage unit is less than a set value, the control system controls the third flow control valve (19) to open, so that the liquid hydrogen storage unit and the liquid hydrogen self-pressurization system form a closed loop; the control system controls the first three-way valve (25) to connect the cooling water pump (24) with the vaporizer cooling pipeline in the liquid hydrogen self-pressurization system, and the control system controls the second three-way valve (27) to connect the vaporizer cooling pipeline in the liquid hydrogen self-pressurization system with the heater.

10. The thermal management method of the self-pressurizing vehicle-mounted liquid hydrogen storage and supply system according to claim 9, characterized in that: When the pressure in the liquid hydrogen storage unit is less than a set value, the control system measures the temperature of the coolant flowing out of the vaporizer in the liquid hydrogen self-pressurizing system according to the third temperature sensor (26), controls the flow of the cooling water pump (24) and the opening of the three flow control valves (19), so that the pressure in the liquid hydrogen storage unit is maintained at 1 to 1.2 times the set value, and the temperature of the coolant flowing out of the vaporizer in the liquid hydrogen self-pressurizing system is controlled at -35°C to -25°C; the coolant flowing out of the vaporizer in the liquid hydrogen self-pressurizing system enters the heat exchanger (17) of the fuel cell stack cooling system, so that the temperature of the deionized water in the fuel cell stack cooling system is reduced to 10 to 20°C.

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